Antibodies play an important role in neutralizing virus and provide protection to the host against viral re-infection. The antibody response to SARS-CoV-2 infection has been extensively studied in the blood of COVID-19 patients in order to gain insights into the host immune response. Understanding their durability and their system compartmentalization across a diverse population are critical pieces of data informing our ability to monitor seroprevalence in communities, to select plasma donors for treatment and to design vaccines against COVID-19.
In a study published in Science Immunology, the researchers examined the stability of antibody levels over the first three months after infection in both the serum and the saliva. It was observed that no drastic decline in levels of anti-spike, anti-RBD, or anti-NP IgG levels over a 3-month period. Given the presence of SARS-CoV-2 RNA in saliva, it is reasonable to hypothesize that, like other viruses such as rubella, the mucosa and draining lymph nodes of the oro-and nasopharyngeal tracts serve as a site for initiation of an immune response to SARS-CoV-2. What does this mean? The researchers claim that the study provides evidence that the IgG response to SARS-CoV-2 spike persists in the saliva and the serum and that this response can be correlated between the two biofluids particularly for IgG. A lot of scientific jargon, true, however interesting information regarding the saliva and seroprevalence! This is exactly the type of hope we need for our times, we need researchers to do what they do, research! Stay well, stay safe, and stay tuned!